Cast bullet size - Need some advice

[Sam Sackett]

I know that the alloy (pure vs WW vs Linotype, etc) will change the as cast diameter of the bullet. Closer to pure will be both smaller and heavier compared to the alloys with more antimony.
BUT. Can someone enlighten me as to how both melt temperature and mould temperature affects the as cast bullet size? I am thinking hotter melt temps will cast a smaller bullet, but hotter mould temps will cast a larger bullet when using the same alloy.

Is this correct, or am I way out in left field looking for a bunt?

Sam Sackett

[Bazoo]

A frosted bullet measures smaller than a not frosted bullet. Hotter mould temperature equals smart bullet. Least that's my experiences. Best I recall, hotter alloys shrink more too but I'm going off what I've read.

[Sam Sackett]

Bazoo, is frosted bullet caused by hot mould, or hot alloy? Or both?

I have read elsewhere on this site that a too hot mould expands and will produce larger bullets.

I have been casting cowboy bullets with almost pure lead, so don't see much frosting..

I'm cornfused.....

Sam

[DHDeal]

I can't help with the specifics of your question as I pay more attention to weight than size on "as cast" bullets. Mine are going to be PC'd shortly after casting and once they get shoved through the sizing die it is what it is.

I've read on here and noticed myself, my higher antimony alloys get fat over time. Not "can't beat them through the throats anymore" fat, but measurable. Lead and it's various alloys are a marvel and though I've cast tens of thousands of bullets, I only know enough to give bad advice on alloys.

[DHDeal]

Frosted bullets IME is caused by a hot mold. I rarely see it with iron or brass molds. I cast about 400 today from an Accurate Molds 45-280C in aluminum, and probably 30% were slightly frosted. If I had been using a sponge to cool the mold, I wouldn't have had that many, but it was about 40° and windy and I didn't think I would need it (I was wrong).

I also don't remember seeing frosted bullets with a binary alloy. Not saying it doesn't happen, I just don't remember seeing it.

[ascast]

Hot mold means bigger hole, so more alloy in hole. It's like heating up a rusted nut to get it off, the hole gets bigger, less grip, comes off. In bullets, you have to measure, test and see if you can live with it. A thermometer will assist in keeping temp constant.

[Conditor22]

the harder the alloy the lower the melt temperature

the hotter the alloy the more the boolit will shrink

frosting has nothing to do with alloy it is heat based

[ABJ]

I don't think I can answer your question completely but I can speak to frosting. I cast a lot of pure lead and 20:1 and a three way alloy of 2% tin and 4% antimony.
The pure lead and 20:1 will not frost at any temp up to 800 degrees. The three way alloy will at 800 on what I call a normal to fast pace. If I drop the alloy temp down to 780 static and add 2 lbs ingot every time the pot has room about 50% have some frosting.

Drop the static temp down to 770 degrees and almost all frosting goes away and a bullet with more glossy and less satin appearance is the result.
Now having said all that, I have shot the frosted boolits against the non frosted in accurate 30-06 and see no difference in accuracy. It is my opinion that the cooler cast boolits result in a larger as cast size, based only on the fact they seem to require more pressure to size in my Star sizer. I have not measured them to verify this. I don't mind a little frosting so I keep my alloy Mag 25 set at 780 degrees.
I hope this is of some help to you.
Tony

[Sam Sackett]

Thanks for the answers. Allow me to paraphrase a bit to see if I understand.

Hot melt produces smaller bullets.
Hot mould with a 3 way alloy produces smaller bullets and maybe frosted if hot enough.
Hot mould and binary(lead/tin) alloy will not noticeably frost.
The consensus seems to be that a hot mould will not produce larger bullets.
To produce the largest bullets from a mould, keep melt AND mould temps as low as possible to drop acceptable bullets.

Sound about right?

Sam

[TomAM]

Hotter mold makes bigger bullets. Period.
The mold block expands with heat, expanding the hole.
Aluminum expands more than brass which expands more than iron. But they all produce larger when hotter.

[Sam Sackett]

Thanks for the good replies.

Sam

[too many things]

800 is hot for most lead, had better luck at 650 but thats just my 2cents